
<template>
  <div>
    <router-link
     tag="div" to="/"
     class="header-abs"
     v-show="showAbs">
      <div class="iconfont header-abs-back">&#xe624;</div>
    </router-link>

    <div class="header-fixed"
         v-show="!showAbs"
         :style="opacityStyle">
      <router-link to="/">
        <div class="iconfont header-fixed-back">&#xe624;</div>
      </router-link>
      景点详情
    </div>
  </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      this.showAbs = !(top > 60)
      if (!this.showAbs) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {opacity}
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
@import '~styles/varibles.styl'
.header-abs
  position absolute
  left 0.2rem
  top 0.2rem
  width 0.8rem
  height 0.8rem
  line-height 0.8rem
  text-align center
  border-radius 0.4rem
  background-color rgba(0,0,0,.8)
  .header-abs-back
    color #fff
    font-size .4rem
.header-fixed
  position: fixed
  z-index 99
  top 0
  left 0
  right 0
  overflow: hidden
  height: $headerHeight
  line-height: $headerHeight
  text-align: center
  color: #fff
  background-color: $bgColor
  font-size: 0.32rem;
  .header-fixed-back
    position: absolute
    top: 0
    left: 0
    width: 0.64rem;
    text-align: center
    font-size: 0.4rem;
    color: #fff
</style>
